Solid metals or alloys are generally crystal state but if a molten metal is cooled at an extremely high speed (the cooling rate depends upon the alloy composition but is approximately 10.sup.4 .degree.-10.sup.6 .degree. C./sec), a solid having a non-crystal structure, which has no periodic atomic arrangement, is obtained. Such metals are referred to as non-crystal metals or amorphous metals. In general, this type metal is an alloy consisting of two or more elements and usually consists of a combination of a transition metal element and a metalloid element and an amount of the metalloid is about 15-30 atomic%.
Japanese Patent Laid-Open Application No. 91,014/74 discloses novel amorphous metals and amorphous metal articles. The component composition of the alloys is as follows.
The amorphous alloys have the following formula EQU M.sub.a Y.sub.b Z.sub.c
wherein M is a metal selected from the group consisting of iron, nickel, chromium, cobalt and vanadium or a mixture thereof; Y is a metalloid selected from phosphorus, carbon and boron or a mixture thereof; Z is an element selected from the group consisting of aluminum, silicon, tin, antimony, germanium, indium and beryllium or a mixture thereof; a, b, and c are about 60-90 atomic%, 10-30 atomic% and 0.1-15 atomic% respectively, a+b+c being 100.
However, the amorphous alloys are ones containing 0.1-15 atomic% of an element selected from the group consisting of aluminum, silicon, tin, antimony, germanium, indium and beryllium or a mixture thereof as the essential component and have drawbacks in the cost of the starting material, the crystallizing temperature, the corrosion resistance, the embrittlement resistance and the like.
The inventors have already discovered Fe-Cr series amorphous alloys (Japanese Patent Laid-Open Application No. 101,215/75) and filed said patent application. The alloys are Fe-Cr series amorphous alloys having high strength, excellent corrosion resistance and heat resistance and consist of 1-40 atomic% of chromium, not less than 2 atomic% of boron, not less than 5 atomic% of phosphorus and 15-30 atomic% of the sum of carbon or boron and phosphorus and the remainder being iron. However, since these alloys contain boron, the cost of the starting material is high, and since these alloys contain phosphorus, the embrittlement resistance is low and when melting, vaporous phosphorus is generated and is harmful. Furthermore, the inventors have already discovered Fe-Cr series amorphous alloys (Japanese Patent Laid-Open Application No. 3,312/76) having high strength and filed this patent application. The alloys involve the following two kind of alloys.
(1) Fe-Cr series amorphous alloys having high strength and excellent heat resistance consisting of 1-40 atomic% of chromium, not less than 0.01% of each content of carbon and boron and the total amount being 7-35 atomic% and the remainder being iron.
(2) Fe-Cr series amorphous alloys having high strength and excellent heat resistance consisting of 1-40 atomic% of chromium, not less than 0.01 atomic% of each content of carbon and boron and the total amount of carbon and boron being 2-35 atomic%, not more than 33 atomic% of phosphorus, and the total amount of carbon, boron and phosphorus being 7-35 atomic% and the remainder being iron.
The above described alloys (1) and (2) are excellent in the heat resistance and high in the strength but since boron is contained, the cost of the starting material is high and the corrosion resistance is not satisfied, and since the alloys (2) contain phosphorus, the embrittlement resistance is low and when melting, the vaporous phosphorus is generated and this alloy is harmful.
Moreover, the inventors have discovered amorphous iron alloys (Japanese Patent Laid-Open Application No. 4,018/76) having high strength and filed such patent application. The alloys are as follows.
(1) Amorphous iron alloys having high strength consisting of 1-40 atomic% of chromium, not less than 2 atomic% of either carbon or boron, not less than 5 atomic% of phosphorus, the total amount of either carbon or boron, and phosphorus being 7-15 atomic% and the remainder being iron.
(2) Amorphous iron alloys having high strength consisting of 1-40 atomic% of chromium, not less than 2 atomic% of either carbon or boron, not less than 5 atomic% of phosphorus, the total amount of either carbon or boron and phosphorus being 30-35 atomic% and the remainder being iron.
The above described alloys (1) and (2) are high in the heat resistance and the mechanical strength but since phosphorus is contained in a relatively large amount, the vaporous phosphorus is generated upon melting and these alloys are harmful.
The inventors have found amorphous iron alloys (Japanese Patent Laid-Open Application No. 4,019/76) having high pitting corrosion resistance, crevice corrosion resistance, stress corrosion resistance and hydrogen embrittlement resistance and filed such patent application. The alloys are the following three kind of alloys.
(1) Amorphous iron alloys having high pitting corrosion resistance, crevice corrosion resistance, stress corrosion resistance and hydrogen embrittlement resistance and consisting of 1-40 atomic% of chromium, not less than 0.01% of each carbon and boron, the total amount being 7-35 atomic% and the remainder being iron.
(2) Amorphous iron alloys having high pitting corrosion resistance, crevice corrosion resistance, stress corrosion resistance and hydrogen embrittlement resistance and consisting of 1-40 atomic% of chromium, not less than 0.01 atomic% of each carbon and boron and the total amount being 2-35 atomic%, not more than 33 atomic% of phosphorus and the total amount of carbon, boron and phosphorus being 7-35 atomic%, and the remainder being iron.
(3) Amorphous iron alloys having high pitting corrosion resistance, crevice corrosion resistance, stress corrosion resistance and hydrogen embrittlement resistance and consisting of 1-40 atomic% of chromium, 2-30 atomic% of either carbon or boron, 5-33 atomic% of phosphorus, the total amount of either carbon or boron and phosphorus being 7-35 atomic% and the remainder being iron.
Among the above described alloys (1), (2) and (3), the alloys (1) and (2) contain boron and the alloys (2) and (3) contain phosphorus, so that the cost of the starting material is high or the embrittlement resistance is low and further the vaporous phosphorus is generated when melting and the alloys are harmful.
The inventors have disclosed amorphous alloys having high permeability and having the following component composition range in Japanese Patent Laid-Open Application No. 73,920/76.
(1) Amorphous alloys having high permeability and consisting of 7-35 atomic% of at least one of phosphorus, carbon and boron and 93-65 atomic% of at least one of iron and cobalt.
(2) Amorphous alloys having high permeability as described in the above described item (1), which further contains not more than 50 atomic% of the total amount of at least one component selected from the following groups
(a), (b), (c), (d) and (e),
(a) not more than 50 atomic% of nickel,
(b) not more than 25 atomic% of silicon,
(c) not more than 15 atomic% of at least one of chromium and manganese,
(d) not more than 10 atomic% of at least one of molybdenum, zirconium, titanium, aluminum, vanadium, niobium, tantalum, tungsten, copper, germanium, beryllium and bismuth and
(e) not more than 5 atomic% of at least one of praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium and holmium.
These alloys have not yet fully satisfied in view of the cost of the starting material, the crystallizing temperature, hardness, strength, embrittling temperature and the like.
Japanese Patent Laid-Open Application No. 5,620/77 discloses amorphous alloys containing iron group elements and boron. The amorphous alloys consist of the following component composition. At least 50% amorphous metal alloys having the following formula EQU M.sub.a M'.sub.b Cr.sub.c M".sub.d B.sub.e
wherein M is at least one element of iron, cobalt and nickel, M' is at least one element selected from the group consisting of iron, cobalt and nickel, which is different from the M element, M" is at least one element selected from the group consisting of vanadium, manganese, molybdenum, tungsten, niobium and tantalum, a is about 40-85 atomic%, b is 0 to about 45 atomic%, c and d are 0-20 atomic% respectively and e is about 15-25 atomic%, provided that when M is nickel, all b, c and d do not become 0.
The alloys contain boron as the essential component, so that there is problem in view of the cost of the starting material and the crystallizing temperature.
The inventors have already discovered amorphous iron alloys having high strength, fatigue resistance, general corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, stress corrosion resistance, and hydrogen embrittlement resistance and filed a patent application (Japanese Patent Laid-Open Application No. 4,017/76). These alloys contain 1-40 atomic% of chromium, and 7-35 atomic% of at least one of phosphorus, carbon and boron as the main component and as the auxiliary component, 0.01-75 atomic% of at least one group selected from the group consisting of
(1) 0.01-40 atomic% of at least one of Ni and Co,
(2) 0.01-20 atomic% of at least one of Mo, Zr, Ti, Si, Al, Pt, Mn and Pd,
(3) 0.01-10 atomic% of at least one of V, Nb, Ta, W, Ge and Be, and
(4) 0.01-5 atomic% of at least one of Au, Cu, Zn, Cd, Sn, As, Sb, Bi and S, and the remainder being substantially Fe.
The above described amorphous alloys are novel ones in which the strength and the heat resistant are improved and the corrosion resistance is provided by adding chromium. These alloys have excellent properties, for example, the fracture strength is within the range of about 1/40-1/50 of Young's modulus and is near the value of the ideal strength and in spite of the high strength, the toughness is very excellent and the fracture toughness value (K.sub.IC) is about 5-10 times as high as the practically used high strength and tough steels (piano steel, maraging steel, PH steel and the like). More particularly, these alloys have novel properties in view of the corrosion resistance and have high resistance against not only the general corrosion, but also the pitting corrosion, crevice corrosion and stress corrosion, which cannot be avoided in the presently used stainless steels (304 steel, 316 steel and the like), but the component composition is broad, so that against the practical and novel use the heat resistance is high, and the hardness and strength are high and the embrittling temperature is high and the production is easy. The cheap component composition range has never been known.
The present invention aims to provide carbon series amorphous alloys which are easy and cheap in the production while holding the above described various properties and articles manufactured from said alloys.